Optical apparatus

ABSTRACT

An optical apparatus includes a light-quantity-adjusting unit, a first lens unit disposed closer to an object than the light-quantity-adjusting unit, a second lens unit disposed closer to an image plane than the light-quantity-adjusting unit, and a drive unit for driving the first lens unit and the second lens unit in an orthogonal-to-optical-axis direction.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to optical apparatuses, such asimage-capturing apparatuses including camcorders and digital stillcameras, and interchangeable lens systems.

2. Description of the Related Art

Image-capturing apparatuses and interchangeable lens systems ofteninclude a blur-compensating device for moving a lens in a directionsubstantially orthogonal to the optical axis (hereinafter, referred toas “orthogonal-to-optical-axis direction”) to bend the optical axis ofthe image-capturing optical system, thereby compensating for image blurcaused by hand movement or the like. Generally, in such ablur-compensating device, a lens unit closer to the image plane(hereinafter referred to as “compensating lens unit”) than alight-quantity-adjusting unit is driven in theorthogonal-to-optical-axis direction (see Patent Document 1: JapanesePatent Laid-Open No. 7-36074, corresponding to U.S. Pat. No. 5,715,479).On the other hand, a lens unit closer to an object (hereinafter referredto as “variator”) than the light-quantity adjusting unit is immovable inthe orthogonal-to-optical-axis direction, and the distance between thevariator and the compensating lens unit, along the optical axis, isfixed.

However, when only the compensating lens unit is driven in theorthogonal-to-optical-axis direction, the freedom of optical design orthe freedom of mechanical design, which involves the drive mechanisms ofthe light-quantity-adjusting unit and compensating lens unit, arelimited. This may become an obstacle to the downsizing of opticalapparatuses.

Moreover, for example, in a zoom-lens system in which the variator ismoved along the optical axis for zooming in and out, when only thecompensating lens unit is driven in the orthogonal-to-optical-axisdirection, the variator cannot be brought close to the compensating lensunit because the light-quantity-adjusting unit is interposedtherebetween. It is thus difficult to improve the zoom efficiency in thezoom-lens system.

SUMMARY OF THE INVENTION

The present invention is directed to an optical apparatus that providesthe structure of a blur-compensating optical system that can contributeto the reduced size of the optical apparatus, and further to improvedzoom efficiency when used in a zoom-lens system.

In one aspect of the present invention, an optical apparatus includes alight-quantity-adjusting unit; a first lens unit disposed closer to anobject than the light-quantity-adjusting unit; a second lens unitdisposed closer to an image plane than the light-quantity-adjustingunit; and a drive unit driving the first lens unit and the second lensunit in an orthogonal-to-optical-axis direction.

Other features and advantages of the present invention will be apparentfrom the following description taken in conjunction with theaccompanying drawings, in which like reference characters designate thesame or similar parts throughout the figures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention and,together with the description, serve to explain the principles of theinvention.

FIG. 1 is a perspective view of a camera according to an embodiment ofthe present invention.

FIG. 2 is an exploded perspective view of a lens barrel included in thecamera shown in FIG. 1.

FIG. 3 is a cross-sectional view of the lens barrel shown in FIG. 2.

FIG. 4 is a cross-sectional view of a shift unit included in the lensbarrel shown in FIG. 2.

FIG. 5 is a perspective view for illustrating a method for integrating alight-quantity-adjusting unit with the shift unit shown in FIG. 4.

FIG. 6 is a perspective view for illustrating the assembling procedurefor the shift unit shown in FIG. 4.

FIG. 7 is a block diagram showing the structure of an electric circuitof the camera shown in FIG. 1.

DESCRIPTION OF THE EMBODIMENTS

The embodiments of the present invention will now be described withreference to the drawings.

FIG. 1 shows the structure of an image-capturing apparatus (hereinafterreferred to as “camera”), such as a camcorder and a digital camera,according to an embodiment of the present invention. Referring to FIG.1, the camera includes a lens barrel L with zooming capabilities and acamera body B. The camera body B includes a silver-salt film or animage-capturing device for recording a subject image formed by animage-capturing optical system in the lens barrel L.

FIGS. 2 and 3 show the structure of the lens barrel L shown in FIG. 1.The image-capturing optical system is a zoom optical system (zoom lenssystem) including four lens units, that is, convex, concave, convex, andconvex lens units, starting from the object side (from the left in eachdrawing). FIG. 4 is a cross-sectional view of a shift unit 3 serving asa blur-compensating device included in the lens barrel L.

Referring to these drawings, the lens barrel L includes a first lensunit L1, a second lens unit L2 for zooming in and out by moving alongthe optical axis AXL (see FIG. 3), and a third lens unit L3 forcompensating for image blur by moving in a plane substantiallyorthogonal to the optical axis (hereinafter referred to as“orthogonal-to-optical-axis plane”), that is, by moving in a directionsubstantially orthogonal to the optical axis (hereinafter referred to as“orthogonal-to-optical-axis direction”). The third lens unit L3 includesa third-a lens subunit L3 a (corresponding to the first lens unit in thefirst aspect of the present invention) and a third-b lens subunit L3 b(corresponding to the second lens unit in the first aspect of thepresent invention) located closer to the image plane than the third-alens subunit L3 a. The lens barrel L further includes a fourth lens unitL4 for focusing by moving along the optical axis.

A front lens barrel 1 holds the first lens unit L1. To secure the firstlens unit L1 in place, the rear end of a fixed barrel 5 is joined to ashift base 312, which serves as a base member for a shift unit 3, whilethe front end of the fixed barrel 5 is joined to the front lens barrel1.

A variator moving frame 2 holds the second lens unit L2. The shift unit3 combines the third-a lens subunit L3 a and the third-b lens subunit L3b in an integrated fashion and moves them in anorthogonal-to-optical-axis direction. A focus moving frame 4 holds thefourth lens unit L4. A rear barrel 6 holds an image-capturing device(photoelectric transducer) 601, such as a charge-coupled device (CCD)sensor and a complementary metal-oxide semiconductor (CMOS) sensor. Therear barrel 6 is joined to the shift base 312 at the front end.

An intermediate member 602 is provided for attaching the image-capturingdevice 601 to the rear barrel 6. After securing the image-capturingdevice 601 to the intermediate member 602 with an adhesive or the like,the intermediate member 602 is fastened to the rear barrel 6 withscrews.

A first guide bar 8 is held by the fixed barrel 5 and the rear barrel 6at both ends. A second guide bar 9 is pressed into and held by the fixedbarrel 5. A third guide bar 10 and a fourth guide bar 11 are held by theshift base 312 and the rear barrel 6.

The variator moving frame 2 is supported by the first guide bar 8 andsecond guide bar 9 movably along the optical axis. The focus movingframe 4 is supported by the third guide bar 10 and fourth guide bar 11movably along the optical axis.

After being positioned with respect to the fixed barrel 5, the shiftunit 3 (shift base 312) is placed between the rear barrel 6 and thefixed barrel 5 and joined to them.

A light-quantity-adjusting unit 7 adjusts the amount of light enteringthe image-capturing optical system. The light-quantity-adjusting unit 7moves two iris blades 702 and 703 in an orthogonal-to-optical-axisdirection to change the aperture diameter. A neutral density filter (NDfilter) 706 for two densities is capable of moving forward and backwardwith respect to the optical path, independent of the iris blades 702 and703. The light-quantity-adjusting unit 7 is fastened to the shift base312 with screws.

The rear barrel 6 is positioned with respect to the fixed barrel 5 andfastened with screws from the back, with the shift base 312 interposedbetween the fixed barrel 5 and the rear barrel 6, as described above. Atthe same time, an engaging projection 603 provided at the upper frontend of the rear barrel 6 is moved into engagement with an engaging hole501 provided at the upper rear end of the fixed barrel 5.

A focus motor (voice coil motor) for driving the fourth lens unit L4along the optical axis includes a coil 401, a drive magnet 402, and ayoke member 403 for closing a magnetic flux. The application of currentto the coil 401 causes a Lorentz force to be generated, because magneticlines of force generated between the drive magnet 402 and the coil 401repel one another. The Lorentz force then drives the focus moving frame4 and the fourth lens unit L4 along the optical axis. The focus movingframe 4 holds a multipolar sensor magnet (not shown) magnetized in theoptical-axis direction. The fixed barrel 5 is provided with amagnetoresistive (MR) sensor 404 fastened, with screws, to the pointopposite the sensor magnet of the focus moving frame 4. The MR sensor404 is capable of detecting variations in magnetic lines of forceassociated with the movement of the sensor magnet. Using signals fromthe MR sensor 404, the amount of travel of the focus moving frame 4,that is, the fourth lens unit L4, from a predetermined referenceposition can be detected.

A stepping motor 201 (corresponding to “zoom motor 33” in FIG. 7) drivesthe second lens unit L2 along the optical axis. The output shaft of thestepping motor 201 is provided with a lead screw 202. The stepping motor201 is fastened through a supporting member to the fixed barrel 5 withscrews. A rack 203 attached to the variator moving frame 2 engages withthe lead screw 202. The application of current to the stepping motor 201causes the lead screw 202 to rotate, thereby driving the second lensunit L2 along the optical axis.

The biasing force of a torsion coil spring 204 prevents the rack 203,the variator moving frame 2, the first and second guide bars 8 and 9,and the lead screw 202 from rattling against one another.

A photo interrupter 205, as shown in FIG. 7, serves as a zoom-resetswitch for detecting a reference position of the variator moving frame2. The photo interrupter 205 detects the switching between alight-blocking mode and a light-transmitting mode, caused by themovement of a light shield 206 arranged in the variator moving frame 2.The photo interrupter 205 is fastened to the fixed barrel 5, with asubstrate interposed therebetween, with a screw 207.

The structure of the shift unit 3 and light-quantity-adjusting unit 7will now be described in detail. In the shift unit 3, the third-a lenssubunit L3 a and the third-b lens subunit L3 b are driven, on theircorresponding orthogonal-to-optical-axis planes, by a pitch actuator forcompensating for image blur caused by angular variations in the verticaldirection (pitch direction) of the camera; and by a yaw actuator forcompensating for image blur caused by angular variations in thehorizontal direction (yaw direction) of the camera.

The camera body B includes, as shown in FIG. 7, a vibration sensor 51and a vibration sensor 52, such as vibration gyro sensors, for detectingangular variations in the pitch direction and the yaw direction. Acontrol circuit 37, such as a CPU for executing the entire control ofthe camera, controls each actuator based on the output from thevibration sensors 51 and 52, and signals from a position sensor(described below) detecting the position of the third-a lens subunit L3a and the third-b lens subunit L3 b on their correspondingorthogonal-to-optical-axis planes. Each drive operation of the pitchactuator and yaw actuator is independently controlled.

The actuator and position sensor for the pitch direction are arranged tobe orthogonal to the actuator and position sensor for the yaw direction.Only the structure for the yaw direction (shown in FIG. 2 and thecross-sectional view in FIG. 4) will be described below, as thestructures for both directions are the same.

A first shift barrel 313 holds the third-a lens subunit L3 a, while asecond shift barrel 314 (corresponding to the second holder in the firstaspect of the present invention) holds the third-b lens subunit L3 b.The first shift barrel 313 includes a lens holder 313 a (correspondingto the first holder in the third aspect of the present invention) forholding the third-a lens subunit L3 a, and a connector 313 b forconnecting the lens holder 313 a and the second shift barrel 314. Toensure the strength of connection, the connector 313 b extends to bothends of the lens holder 313 a (corresponding to the two points along thefirst orthogonal-to-optical-axis direction in the third aspect of thepresent invention). The first shift barrel 313 and the second shiftbarrel 314 are bonded together with an adhesive 313 c, after theadjustment to align the optical axes of the third-a lens subunit L3 aand the third-b lens subunit L3 b in order to remove the relativeeccentricity between the first shift barrel 313 and the second shiftbarrel 314.

Since the first shift barrel 313 (connector 313 b) and the second shiftbarrel 314 are bonded together, the distance between the third-a lenssubunit L3 a and the third-b lens subunit L3 b, along the optical axis,is kept constant (fixed). In practice, the third-a lens subunit L3 a andthe third-b lens subunit L3 b move together to bend the optical axis AXLfor image-blur compensation.

A magnet 303 providing both a driving purpose and a position-detectingpurpose is pressed into and held by a magnet base 301. Since the magnet303 is pressed and fitted into the magnet base 301, the positionalrelationship between the magnet 303 and the magnet base 301 ismaintained. Since the magnet base 301 is fastened with a screw 315 tothe first shift barrel 313 to which the second shift barrel 314 hasalready been bonded, the magnet 303 can be positioned at a fixed pointwith respect to the third-a lens subunit L3 a and the third-b lenssubunit L3 b. As such, the magnet 303 can accurately detect thepositions of the third-a lens subunit L3 a and the third-b lens subunitL3 b.

The magnet base 301 is secured, with the screw 315, to the first shiftbarrel 313 with a metal plate 304 interposed therebetween. Stainlesssteel or the like is suited as a material for the metal plate 304.

Three balls 309 on an orthogonal-to-optical-axis plane are interposedbetween the shift base 312 and the magnet base 301, and are arrangedaround the optical axis. The metal plate 304 described above is disposedbetween the balls 309 and the magnet base 301. Even if the camerareceives a shock, the metal plate 304 prevents the balls 309 fromcausing dents on the molded magnet base 301, thereby preventing thedrive performance of the shift unit 3 from being degraded. Substantiallyu-shaped ball holders 310 made of stainless steel or the like aredisposed between the balls 309 and the shift base 312. The ball holders310 are pressed into holes 312a (see FIG. 2) provided in the shift base312 and hold the corresponding balls 309 rotatably therein.

The balls 309 can be made of stainless steel or the like, so as not tobe attracted to the magnet 303 disposed in the vicinity thereof.

It is the force of attraction between the magnet 303 and a rear yoke 311that allows the balls 309 to be reliably in contact with the shift base312 (end surfaces of the ball holders 310 orthogonal to the opticalaxis) and with the magnet base 301 (metal plate 304). This force ofattraction causes the magnet base 301 to be biased toward the shift base312, thereby pressing the three balls 309 into contact with theabove-described end surfaces of the ball holders 310, and with threepoints on the metal plate 304. The surfaces with which the three balls309 are in contact extend in the direction orthogonal to the opticalaxis AXL of the image-capturing optical system. The three balls 309 havethe same nominal diameter. Therefore, it is possible to move the thirdlens unit L3 in the orthogonal-to-optical-axis plane without causing itto lean towards the optical axis, by minimizing the amount ofdisplacement, along the optical axis, between the end surfaces of thethree ball holders 310, and by minimizing the amount of displacement,along the optical axis, between the above-described three points on themetal plate 304.

Thus, the force of attraction between the magnet 303 and the rear yoke311 for biasing the magnet base 301 towards the shift base 312eliminates the need for parts for biasing, such as springs, and canreduce the size of the shift unit 3.

Actuators for driving the magnet base 301 and the third lens unit L3will now be described. As described above, the magnet 303 is magnetizedand polarized radially from the optical axis AXL, as shown in FIG. 3. Afront yoke 302 is provided for closing the magnetic flux, along theoptical axis, in front of the magnet 303. The front yoke 302 isattracted and secured to the magnet 303. A coil 308 is bonded to theshift base 312. The rear yoke 311 is provided for closing the magneticflux, along the optical axis, behind the magnet 303. The rear yoke 311is arranged opposite the magnet 303 with the coil 308 interposedtherebetween, and is held by the shift base 312. The magnet 303, thefront yoke 302, the rear yoke 311, and the coil 308 constitute amagnetic circuit.

When a current is applied to the coil 308, magnetic lines of forcegenerated between the magnet 303 and coil 308 repel one another in thedirection substantially orthogonal to the magnetic boundary of themagnet 303, and cause a Lorentz force, which moves the magnet base 301in the orthogonal-to-optical-axis direction. This is a so-calledmoving-magnet-type actuator.

Since actuators with such a structure are provided at respectivevertical and horizontal directions, it is possible to drive the magnetbase 301 and the third lens unit L3 in two orthogonal-to-optical-axisdirections intersecting at substantially right angles. The combinationof the vertical and horizontal driving thus allows the magnet base 301and third lens unit L3 to move freely within a predetermined area on theorthogonal-to-optical-axis plane.

Friction on the movement of the magnet base 301 in theorthogonal-to-optical-axis direction is only rolling friction betweenthe balls 309 and the metal plate 304, and between the balls 309 and theball holders 310. Therefore, despite the force of attraction acting asdescribed above, the magnet base 301 (that is, the third lens unit L3)can move extremely smooth, and fine control over the amount of travelcan be made. The application of lubricating oil to the balls 309 allowsfor a further reduction in friction.

Position detection of the magnet base 301 and third lens unit L3 willnow be described. A hall element 307 for converting a magnetic fluxdensity into electric signals is soldered to a flexible print cable(hereinafter referred to as FPC) 306. The FPC 306 is positioned withrespect to the shift base 312 and secured. Securing an FPC retainer 305with a screw 316 to the shift base 312 prevents the loosening of the FPC306 and the positional displacement of the hall element 307. A positionsensor for detecting the position of the magnet base 301 and third lensunit L3 is thus provided.

When the magnet base 301 and the third lens unit L3 are drivenvertically or horizontally, the hall element 307 detects changes inmagnetic flux density and outputs electric signals indicating thechanges therefrom. Based on the electric signals from the hall element307, the control circuit 37 can detect the position of the magnet base301 and the third lens unit L3. The magnet 303 not only serves as amagnet for driving, but also serves as a magnet for position detection.

The relationship between the shift unit 3 and thelight-quantity-adjusting unit 7 will now be described with reference tothe drawings including FIG. 5. In the vicinity of the optical axis, thelight-quantity-adjusting unit 7 has the thickness formed by a retainingplate 701, the iris blade 702, the iris blade 703, a partition plate704, an iris bottom board 705, and the ND filter 706 that are layeredalong the optical axis. A prepared hole 319 for a self-tap screw isprovided in the shift base 312. A mounting base 708 is to be interposedbetween a screw 707 and the shift base 312. The above-describedthickness part, which is from the retaining plate 701 to the ND filter706, is inserted, from the direction orthogonal to the line connectingboth ends of the connector 313 b (corresponding to the secondorthogonal-to-optical-axis direction in the third aspect of the presentinvention), into a space 317 defined by the lens holder 313 a in thefirst shift barrel 313, the second shift barrel 314, and the connector313 b at both sides. After the insertion, the light-quantity-adjustingunit 7 is secured to the shift base 312, at the mounting base 708, withthe screw 707. The thickness part is thus interposed between the third-alens subunit L3 a and the third-b lens subunit L3 b.

The assembling procedure of the shift unit 3 and thelight-quantity-adjusting unit 7 will now be described with reference toFIG. 6. The shift unit 3 of the present embodiment includes a shiftmagnet unit 350, a coil unit 351, and a shift-moving-frame unit 352. Theshift magnet unit 350 mainly includes the magnet 303 and the front yoke302. The coil unit 351 mainly includes the coil 308, the hall element307, and the rear yoke 311. The shift-moving-frame unit 352 mainlyincludes the third-a lens subunit L3 a, the third-b lens subunit L3 b,the first shift barrel 313, and the second shift barrel 314.

In the shift magnet unit 350, the magnet 303 is first pressed into themagnet base 301. Then, the front yoke 302 is slid and pressed, in theorthogonal-to-optical-axis direction, into the magnet base 301.

In the coil unit 351, the rear yoke 311 is first slid and pressed, inthe orthogonal-to-optical-axis direction, into the shift base 312. Anadhesive may be applied to a boundary 353 between the rear yoke 311 andthe shift base 312 to more firmly secure the rear yoke 311 to the shiftbase 312. The coil 308 is fitted in the shift base 312 along the opticalaxis. The FPC 306 to which the hall element 307 has already beensoldered is placed on the coil 308. Then, the FPC retainer 305 is placedon a hook 354, and fastened with the screw 316 to the shift base 312 toretain the coil 308 and the FPC 306.

The first shift barrel 313 crimping the third-a lens subunit L3 a, andthe second shift barrel 314 crimping the third-b lens subunit L3 b arebonded with the adhesive 313 c, as described above, to form theshift-moving-frame unit 352.

After the ball holders 310 and the balls 309 are placed on the coil unit351, the connector 313 b of the shift-moving-frame unit 352 and shiftmagnet unit 350 are assembled, with the coil unit 351 and the shift base312 being partially interposed therebetween, to form the shift unit 3.At the same time, a flange 355 for the first shift barrel 313 and aprepared screw hole are fitted into an opening 312 b of the shift base312 to pass through, along the optical axis, to reach the front. Then,in front of the shift base 312, the flange 355 and the prepared screwhole are secured, with the screw 315, to the magnet base 301 in theshift magnet unit 350.

As described above, the shift-moving-frame unit 352 and the shift magnetunit 350 are assembled together, with the coil unit 351 and the shiftbase 312 being partially interposed therebetween, and secured.Therefore, even if a shock exceeding the force of attraction between themagnet 303 and the rear yoke 311 is-applied to the front of the camera,the connector 313 b in the shift-moving-frame unit 352 is brought intocontact with a part of the coil unit 351 or the shift base 312, andserves as a stopper. Moreover, even if such a shock is applied to theback of the camera, the balls 309 serve as a stopper to prevent theshift-moving-frame unit 352 from falling from the shift unit 3 and beingdisabled.

Since the connector 313 b to integrate the third-a lens subunit L3 a andthe third-b lens subunit L3 b is used as a stopper, no additionalstopper other than the connector 313 b is required. This can simplifythe structure of the shift unit 3, and can contribute to the sizereduction of the lens barrel.

The shift magnet unit 350 and the coil unit 351 are arranged in front ofthe connector 313 b, along the optical axis, and are arranged closer tothe optical axis AXL than the connector 313 b. In the presentembodiment, the space around the third lens unit L3 is reduced by theaddition of the connector 313 b. However, the above-describedarrangement allows the shift magnet unit 350 and the coil unit 351 to beplaced without increasing the diameter of the lens barrel.

After the completion of the shift unit 3, the light-quantity-adjustingunit 7 is inserted into the space 317 in the shift-moving-frame unit 352and fastened to the shift base 312 with the screw 707. Since, asdescribed above, the light-quantity-adjusting unit 7 is inserted intoand fastened to the shift-moving-frame unit 352 with the screw 707 lateron, performance evaluations on the shift unit 3 can be separately andthus easily performed before installing the light-quantity-adjustingunit 7. The installation of the light-quantity-adjusting unit 7 itselfis also easy.

A method for determining the center position of the third lens unit L3will now be described with reference to FIGS. 4 and 6. Walls 318provided on the inner side of the opening 312 b in the shift base 312serve as references for the alignment of the optical axis. The distancefrom the optical axis to each wall 318 is designed to be equal. Althoughonly two walls 318 are shown in the horizontal cross-sectional view inFIG. 4, there are another two walls 318 vertically arranged. That is, atotal of four walls 318 are provided.

First, a movable part including the shift-moving-frame unit 352 and theshift magnet unit 350 is moved in an I direction shown in FIG. 4, whichis an orthogonal-to-optical-axis direction, and in the directionorthogonal to the I direction, so as to strike the walls 318 and readthe output from the hall element 307 at each point struck by the movablepart. A position corresponding to the center of the output read from thehall element 307 (hereinafter referred to as “center position”) is theposition in which the optical axis of the third lens unit L3 is alignedwith the optical axis AXL of the image-compensating optical system. Thisposition is stored in a memory included in the camera body B. When noimage blur occurs in the camera, the application of current to the coil308 is controlled such that the movable part is held in the centerposition.

The shift base 312 contributes to the reduction in the number of partssince, as described above, it not only provides the walls 318 fordetermining the center position for the movable part, but also serves asa holding member for holding the coil 308 and the rear yoke 311.

FIG. 7 shows the electrical structure of the camera according to thepresent embodiment. The lens barrel components that are the same asthose described in FIGS. 1 to 6 are denoted by the same referencenumerals.

The zoom motor 33 corresponds to the stepping motor 201 serving as adrive source for the second lens unit L2. A focus motor (voice coilmotor) 34 corresponds to the coil 401 serving as a drive source for thefourth lens unit L4.

An iris motor 35, such as a stepping motor, serves as a drive source forthe light-quantity-adjusting unit 7.

The photo interrupter 205 is a zoom-reset switch for detecting whetheror not the second lens unit L2 is located at a reference position in theoptical-axis direction. After detecting that the second lens unit L2 islocated at the reference position, the photo interrupter 205 can detectthe amount of travel (position with respect to the reference position)of the second lens unit L2, along the optical axis, by continuouslycounting the number of pulse signals inputted into the stepping motor201.

An iris encoder 709 is provided, for example, for a hall elementarranged in the iris motor 35 to detect the positional relationshipbetween a rotor and a stator.

The control circuit 37, such as a CPU, executes the control of thecamera. A camera-signal processing circuit 38 applies predeterminedsignal processing, such as amplification and gamma correction, to theoutput from the image-capturing device 601. Then, contrast signals forthe processed image signals are supplied to an autoexposure (AE) gate 39and to an autofocus (AF) gate 40. The AE gate 39 and the AF gate 40 setthe ranges of signal extraction most appropriate for exposure controland focusing, respectively, based on image signals in the entire imagearea. Each gate may be variable in size, and a plurality of gates may beprovided.

An AF-signal processing circuit 41 processes AF signals for autofocus,and generates one or a plurality of outputs for high-frequencycomponents of image signals.

For zooming in and out, a zoom-tracking memory 43 stores positionalinformation of a focusing lens (fourth lens unit L4) based on thecamera-subject distance and the position of a variator (second lens unitL2). Alternatively, a memory in the control circuit 37 may be used as azoom-tracking memory.

For example, when a user manipulates a zoom switch 42, the controlcircuit 37 controls the drive operation of the zoom motor 33 and thefocus motor 34 such that a predetermined positional relationship,determined based on the information stored in the zoom-tracking memory43, between the second lens unit L2 and the fourth lens unit L4 can bemaintained. Specifically, the control circuit 37 controls the driveoperation of the zoom motor 33 and the focus motor 34 such that a countvalue indicating the current absolute position of the second lens unitL2, along the optical axis, matches a determined position at which thesecond lens unit L2 should be set. At the same time, a count valueindicating the current absolute position of the fourth lens unit L4,along the optical axis, matches a determined position at which thefourth lens unit L4 should be set.

In autofocus operation, the control circuit 37 controls the driveoperation of the focus motor 34 such that the output of the AF-signalprocessing circuit 41 reaches its peak value.

To provide proper exposure, moreover, the control circuit 37 controlsthe drive operation of the iris motor 35, using the mean value of theoutput of Y signals passed through the AE gate 39 as a reference value,such that the output of the iris encoder 709 matches the referencevalue, thereby controlling the amount of light.

Furthermore, the control circuit 37 controls the application of currentto each coil 308, based on the output from the pitch-direction vibrationsensor 51 and the yaw-direction vibration sensor 52 and on signals fromthe MR sensor 404, thereby driving the third lens unit L3 for image-blurcompensation.

As described above, in the present embodiment, the third-a lens subunitL3 a and the third-b lens subunit L3 b disposed in front of and behindthe light-quantity-adjusting unit 7 are driven, in anorthogonal-to-optical-axis direction, to execute image-bluecompensation.

In other words, the third-a lens subunit L3 a that is conventionallydisposed behind the light-quantity-adjusting unit 7 is switched with thelight-quantity-adjusting unit 7, in the present embodiment. In thiscase, when the second lens unit L2 capable of zooming in and out ismoved to the back end of the range of movement, the second lens unit L2and the third-a lens subunit L3 a can be brought closer together thanthey conventionally are. Zoom efficiency (that is, the amount of zoomratio with respect to the travel distance of the second lens unit L2)can thus be improved without increasing the total length of thezoom-lens optical system. The optical apparatus that is compact but hashigh zoom efficiency can thus be achieved.

In the present embodiment, a moving-magnet-type actuator is used todrive the third lens unit L3. The present invention can also be appliedto the case in which a moving-coil-type actuator, which includes a coilat the third lens unit L3 side and a magnet at the shift base 312 side,is used to drive the third lens unit L3.

Moreover, in the present embodiment, the third-a lens subunit L3 a andthe third-b lens subunit L3 b are driven in an integrated fashion alongan orthogonal-to-optical-axis direction. The present invention can alsobe applied to the case in which the third-a lens subunit L3 a and thethird-b lens subunit L3 b are driven separately (independently). In thiscase, a different drive actuator is provided for each of the third-alens subunit L3 a and the third-b lens subunit L3 b.

Furthermore, while the image-capturing apparatus, which is an integratedcombination of the lens barrel and the camera body, has been describedin the present embodiment, the present invention can also be applied toremovable and interchangeable lens systems, and to optical apparatuses,such as viewing apparatuses including binoculars having an antivibrationfunction.

The present invention not only contributes to the downsizing of anoptical apparatus that includes a blur-compensating optical system, butalso improves the zoom efficiency in a zoom lens system.

As many apparently widely different embodiments of the present inventioncan be made without departing from the spirit and scope thereof, it isto be understood that the invention is not limited to the specificembodiments thereof except as defined in the claims.

This application claims priority from Japanese Patent Application No.2004-103225 filed Mar. 31, 2004, which is hereby incorporated byreference herein.

1. An optical apparatus comprising: a light-quantity-adjusting unit; afirst lens unit disposed closer to an object than thelight-quantity-adjusting unit; a second lens unit disposed closer to animage plane than the light-quantity-adjusting unit; and a drive unitdriving the first lens unit and the second lens unit in anorthogonal-to-optical-axis direction.
 2. The optical apparatus accordingto claim 1, further comprising a holding member holding the first lensunit and the second lens unit, wherein the drive unit drives the holdingmember in the orthogonal-to-optical-axis direction.
 3. The opticalapparatus according to claim 2, wherein the holding member includes: afirst holder holding the first lens unit; a second holder holding thesecond lens unit; and a connector connecting the first holder and thesecond holder at two points along a first orthogonal-to-optical-axisdirection, and wherein the light-quantity-adjusting unit is inserted anddisposed into a space defined by the first holder, the second holder andthe connector, from a second orthogonal-to-optical-axis directionorthogonal to the first orthogonal-to-optical-axis direction.
 4. Theoptical apparatus according to claim 2, further comprising: a basemember movably supporting the holding member in theorthogonal-to-optical-axis direction; the holding member including: afirst holder holding the first lens unit; a second holder holding thesecond lens unit; and a connector connecting the first holder and thesecond holder; and the drive unit including a coil and a magnet, whereinat least one of the coil and the magnet is attached to the holdingmember and the other one of the coil and the magnet is attached to thebase member, and wherein the other one of the coil and the magnetattached to the base member is disposed between the one of the coil andthe magnet attached to the holding member and the connector, in theoptical-axis direction.
 5. The optical apparatus according to claim 2,wherein the holding member includes: a first holder holding the firstlens unit; a second holder holding the second lens unit; and a connectorconnecting the first holder and the second holder, and wherein the driveunit is disposed closer to an optical axis than the connector.
 6. Theoptical apparatus according to claim 1, wherein a distance between thefirst lens unit and the second lens unit, in an optical-axis direction,is fixed.
 7. The optical apparatus according to claim 1, furthercomprising a third lens unit disposed closer to the object than thefirst lens unit, wherein the third lens unit facilitates zooming in andout by moving in an optical-axis direction.